June 2021

Fighting False Claims about Folic Acid

It’s well-established that taking folic acid during pregnancy helps reduce the risk of neural tube defects in newborn babies. Unfortunately, there’s some buzz online that taking folic acid can be toxic if you have a variation in a specific gene known as methylenetetrahydrofolate reductase (MTHFR). There’s no evidence supporting these claims.

MTHFR is an enzyme that converts folic acid into its active form. The MTHFR gene controls the creation of this enzyme. People with variations in this gene can have lower levels of MTHFR, and this can result in lower levels of active folate in the body. Having an MTHFR variant is actually fairly common, but people are only recently becoming aware of its presence due to easy access to genetic testing with consumer-targeted companies like 23andMe. This is leading to an increase in concerns about variations to this gene.

There’s a growing list of studies claiming to link MTHFR variants to all sorts of conditions – most of these associations are very weak. Unfortunately, the claim that’s getting the most attention relates to folic acid. Some online “experts” are advising people with an MTHFR variant to cut folic acid out of their diet entirely or to take a special supplemental form of folate, such as L-methylfolate - Quatrefolic and Metafolin are two branded forms of L-methylfolate that are promoted for use in place of folic acid. There’s no evidence to support these recommendations. Even if MTHFR variants may be linked to certain conditions, there's no evidence that avoiding folic acid supplements or taking specific forms of folic acid can help to avoid these conditions.

Explain to your patients that cutting folate out of the diet isn’t safe or necessary. Even in people with MTHFR variants, folic acid is safe and can boost levels of active folate in the body. Claims suggesting otherwise are not supported by any strong scientific evidence. Most importantly, emphasize to your pregnant patients that taking a supplement containing 400 mcg of folic acid daily while also consuming folate in the diet is the best way to protect the unborn baby from neural tube defects. 

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